Ignition timer



Feb. 26, 1935. M. MALLORY IGNITION TIMER Filed May 9, 1932 2 She'ets -Sheet l M. MALLORY IGNITION TIMER Feb. 26, 1935.

Filed May 9, 1932 2 Sheets-Sheet 2 Patented Feb. 26, 1935 PATENT OFFICE IGNITION TMER Marion Mallory, Toledo, Ohio, assignor to The Mallory Research Company, a corporation of Delaware Application May 9, 1932, Serial No. 610,123

8 Claims.

a gasoline engine, in which the advance or retardation of the spark is controlled or modified by suction from the intake manifold of the engine. In connection with such control, the spark is usually advanced primarily by a centrifugal governor and a brake is provided to resist such advance under predetermined operating conditions, as for example, when the engine is operating under a heavy load or when the throttle is opened suddenly.

The object of the present invention is to provide improved means for resisting or retarding the advance of the spark under the conditions stated, and to that extent constitutes an improvement over the construction shown in my co-pending application, Serial No. 565,454.

In explaining my invention in detail, reference will be had to the accompanying drawings, in which- Figure 1 is a central vertical section of the timer and the controlling means therefor;

Figure 2 is a section taken on the line 2--2 of Figure 1;

Figure 3 is a section taken on the line 3-3 of Figure 1;

Figure 4 is a section taken on the line 44 of Figure 1;

Figure 5 is a section taken on the line 55 of Figure 1;

Figure 6 is a section taken on the line 6-6 or Figure4;

Figure '7 is a central vertical section of a modified form of the invention;

Figure 8 is a section taken on the line 88 of Figure '7;

Figure 9 is a section taken on the line 9-9 of Figure 7;

Figure 10 is a section taken on the line 1010 of Figure '7;

Figure 11 is a section taken on the line 11-11 of Figure 10. 7

As shown in the drawings, my invention is associated with an ignition timer comprising a housing 15 formed with a bearing 16 for the timer shaft 17. A sleeve 18 is mounted for relative circumferential movement on the shaft 17, and is provided with a cam 19 which actuates the circuit breaker 20. The sleeve 18 is formed with a peripheral flange 21 to which a circular plate 22 is secured, preferably by means of machine screws 23 and a clamping collar 24. Through the medium of plate 22 the relative position of the sleeve 18 with reference to the shaft 17 is controlled to vary the timing of the ignition.

(Cl. 123--117) 1 This invention relates to an ignition timer for As illustrated in Figures 1 to 6, a second circular plate 25 is mounted for circumferential movement with reference to the shoulder 21 between the collar 24 and the plate 22.

The primary control of the spark in accordance with the speed of operation is effected by a speed governor comprising centrifugal weights 26 pivotally mounted on pins 27 which are secured to the plate 22. Each weight 26 also has a downwardly projecting pin 28 which engages a slot 29 formed in a plate 30 which is secured to the shaft 1'7 by means of a nut 31 or other suitable means. The slots 29 have a predetermined inclination or eccentricity with reference to the pins 27 so that the expansion of the governor weights under the influence of centrifugal force, when the timer is rotating in the direction indicated by the arrow in Figure 3, causes an advance of the plate 22 with reference to the plate 30. In the absence of other controlling means, therefore, the advance of the spark will depend wholly upon the'speed of rotation, and the ratio of advance, as well as the maximum limit of the advance, may be varied by varying the inclination and length of the slots 29.

It is desirable, however, as explained more fully in the above mentioned co-pending application, to provide means for retarding or resisting the spark advance under certain operating conditions in accordance with the amount of compression in the cylinders or the degree of vacuum formed in the intake manifold. In the construction shown in Figures to 6, I have provided coil springs 32, each con" necting a pin 33 on one of the weights 26 to a lug 34 secured to or formed integral with the plate 25. Slots 35 are formed'in the plate 22 in order to permit the pins 33 to move outwardly with the weights 26, and wider slots 36 are formed in the plate 25 to permit a circumferential movement of the plate 25 withreference to the plate 22 without interfering with the pins 33. This relative circumferential movement of the plate 25 is limited by the edges of the slots 23 through which the screws 23 pass. In order to modify the effect of the centrifugal governor upon the time the periphery of the plate 25 is adapted to be engaged by a brake shoe 37 carried by a plunger 38 which is mounted for reciprocation in a housing 39 forming a radial extension of the timer housing 15. A conduit 40 connects the plunger housing 39 with the intake manifold 41 or some other part of the fuel intake passageway. An expansile coil spring 42 within the housing 39 bears against the plunger 38 and has a tendency to hold the brake shoe 37 in contact with the plate 25 to retard the action of the centrifugal governor. This spring also-bears against a skeleton seat or spider 43 which is preferably provided with a screw adjustment 44 to vary the tension of the spring.

In the operation of the timer, if the engine is operating with a comparatively light load, so that the fuel charge is small as compared with the speed of the engine, the vacuum in the manifold 41 will be suflicient to overcome the tension of the spring 42 and withdraw the brake from contact with the plate 25. The timing of the spark will then be completely under the control of the centrifugal governor. If, however, the throttle is suddenly opened wide, relieving the vacuum in the manifold 41, and increasing the compression in the cyl-' inders, the brake will immediately engage the plate 25 and, through the springs 32, will retard the spark until the speed of the engine increases in proportion to the amount of fuel supplied. The spark will likewise be retarded when the engine is operating under a. heavy load since, under such conditions, a greater amount of fuel is supplied in proportion to the speed of the engine, which tends to relieve the vacuum in the manifold 41.

In the drawings, for the sake of simplicity in explaining the operation of the invention, the various parts are shown in the positions which they assume when there is sufficient vacuum in the manifold to retract the brake plunger 38, and while the engine is not yet operatingwith sufficient speed for the centrifugal governor to advance the spark. Referring now to Figures 1 to 6, it will be noted that the springs 32 are under sufficient tension to hold the weights 26 in their innermost positions with the pins 28 engaging the inner ends of the slots 29. When the speed increases sufiiciently for the centrifugal force to force the weights outwardly in opposition to the springs 32, the inclination of the slots 29 forces the pivot pins 27 forwardly and consequently forces the plate 22 forwardly to advance the spark. As the pins 33 move outwardly, the springs 32 are length- .ened and the tension thereof progressively in creased until, at a predetermined speed, theweights reach their outermost position with the pins 33 or 28 engaging the outer ends of their respective slots. This determines the maximum spark advance. Assuming now that a heavy load is imposed upon the engine, or that the throttle is suddenly opened to increase the speed thereof, the vacuum within the intake manifold will be relieved sufliciently to permit the brake 37 to engage the plate 25. This retards the movement of the plate 25 until the pins 33 engage the front edges of the slots 36. This, of course, increases the length and the tension of the springs 32 so that the latter impose a greater resistance upon the centrifugal movement of the governor weights 26. It follows, then, that the expansion of the governor and the advance of the spark is retarded or delayed until the speed is further increased or the throttle closed sufficiently to develop enough vacuum to again retract the brake 37.

In the form of the invention shown in Figures '7 to 11, the timer rotates in a direction opposite to that shown in Figures 1 to 6. The

pins 27", on which the weights 26 are pivoted,

are therefore secured to the plate 30, instead of being secured to the plate '22,as are the pins 27, and the. eccentric slots 29, which are engaged by the pins 28, are formed in the plate 22 and approximately parallel to the slots 35.

Instead of the coil springs 32, leaf springs 45 are secured to the lugs 34 by screws 46 or other a fective force of the springs 45 and causing the action of the governor to be retarded or delayed under the same conditions as the governor shown in Figures 1 to 6.

In the operation of the invention under normal operating conditions, sufiicient vacuum will throttle is suddenly opened or if the engine labors under a heavy load, so that the vacuum in the intake is relieved sufficiently to permit the engagement of the brake with the plate 25, the retardation of the latter increases the tension of the springs, thus rendering the secondary control effective, with the result that the action of the governor is delayed or retarded. If the spark has already been advanced by the governor, a sudden wide opening of the throttle will set the brake and immediately retard the spark, until the speed is further increased. Thus, a sudden opening of the throttle with a resultant increase in compression will not cause a spark knock, because the spark will beretarded. An increase in the load will have a similar result.- It will be noted, however, that the application of the brake to the plate 25 retards the spark only by modifying the action of the centrifugal governor through an increase in the tension of the springs.

It is to be understood that my invention includes all such modifications as may fall within the scope of the appended claims.

What I claim as new, and desire to secure by United States Letters Patent, is:

1. In an ignition system for internal combustion engines, a circuit breaker cam, a timer shaft, a speed responsive device for advancing said cam with relation to the shaft, a member mounted for limited circumferential movement relative to said cam and said shaft, means dependent upon the degree of vacuum in the engine intake to control said circumferential movement, and means controlled by the relative circumferential movement of said member to modify the action of said speed responsive device as compared to the speed of operation.

2. In an ignition system for internal combustion engines, a circuit breaker cam, a timer shaft, a speed responsive device for advancing said cam with relation to the shaft, a spring opposing the action of the speed responsive device, a member mounted for limited circumferential movement relative to said cam and said shaft, and means dependent upon the degree of vacuum in the engine intake to control said circumferential movement, and means controlled by the relative circumferential movement of said member to increase the tension of said spring.

mounted for limited circumferential movement relative to said cam and said shaft, frictional means tending to offer increased resistance to the rotation of said member upon an increase in the amount of fuel supplied for each revolution of the engine.

4. In an ignition system for internal combustion engines, a circuit breaker cam, a timer shaft, a speed responsive device for advancing said cam with relation to the shaft, a spring opposing the action of the speed responsive device, a member mounted for limited circumferential movement relative to said cam and said shaft, frictional means tending to offer increased resistance to the rotation of said member upon an increase in the amount of fuel supplied for each revolution of the engine, and means controlled by the relative circumferential movement of said member to vary the tension of said spring.

5. In an ignition system for internal combustion engines, a circuit breaker cam, a timer shaft, a speed responsive device for advancing said cam with relation to the shaft, a member mounted for limited circumferential movement relative to said shaft and said cam, a brake, a spring tending to apply said brake to said member to resist rotation thereof, means for applying suction to said brake from the fuel intake passageway to resist the action of said spring, and means controlled by the relative circumferential movement of said member to modify the action of said speed responsive device as compared to the speed.

6. In an ignition system for internal combustion engines, a. timer shaft, a circuit breaker cam, a plate secured to the timer shaft, 8. second plate mounted in fixed relation to said cam and having a. limited circumferential movement with respect to said shaft, a centrifugal governor weight pivoted to one of said plates and having a pin and slot connection with the other, said slot being inclined in a direction to cause a spark ad vance with the centrifugal movement of said governor weight, a third plate movable circumferentially with respect to said shaft and said cam and having a spring connection to progressively resist centrifugal movement of the governor weight, and means to resist rotation of said third plate under predetermined operating'conditions.

7. In an ignition system for internal combustion engines, a primary control means for pro-, gressively advancing the spark as the speed of operation increases above a predetermined point, spring means resisting such advance, and secondary control means operable under predetermined operating conditions to increase by a definite amount the tension-of said spring means which resists the initial advance of the spark by the primary control means.

8. In an ignition system for internal combustion engines, a speed responsive device tending to advance the spark as the speed of theengine increases, spring means resisting suchadvance, and means rendered effective by a predetermined variation in the degree of vacuum in the fuel intake passageway to vary the tension of said spring means which resists the initial action of said speed responsive device.

MARION MALLORY. 

